1. Field of the Invention
The present invention relates to a hood motor of a gas range, and more particulary to a driving controlling apparatus of a hood motor for switching on/off the driving of the hood motor and for controlling the rotational speed of a hood motor.
2. Description of the Related Art
Generally, a hood motor ventilates hot-air generated from the lower side of a gas range, and the odor of foods being cooked. Such a hood motor includes a driving controlling apparatus for starting/stopping the driving of the motor, and for controlling the rotational speed of the motor by using a temperature sensor installed therein for sensing the temperature rise.
FIG. 1 is a circuit diagram for showing a conventional driving controlling apparatus of a hood motor.
As shown in FIG. 1, the conventional driving controlling apparatus of the hood motor includes a hood motor 1, a thermal cut out (hereinafter called TCO), a motor driving relay 2, and a motor rotational speed switching relay 3.
The hood motor 1 includes a temperature protector (hereinafter called T/P), inductors L1, L2, and L3, and a capacitor C. Between the inductors L2 and L3 of the hood motor 1, a low-velocity transfer contact L of the motor rotational speed switching relay 3 is connected, while a high-speed transfer contact H is connected between the inductors L1 and L3 of the motor rotational speed switching relay 3.
Further, the motor driving relay 2 includes an exciting coil which is connected with a motor driving button, while both ends of the TCO are connected with a switching terminal T1 and a switching-on contact, respectively.
The exciting coil of the motor rotational speed switching relay 3 is connected with a speed switching button which is manipulated by a user, while another switching terminal T2 is connected with the switching-on contact of the motor driving relay 2.
In the driving controlling apparatus of the hood motor constructed as above, when the user wants to ventilate the gas range, the user manipulates the motor driving button to connect the switching terminal T1 of the motor driving relay 2 to the switching-on contact. Accordingly, commonly used alternating current (hereinafter called AC power) is applied to the hood motor 1, so that the hood motor 1 is rotatably driven.
In such a situation, when the user manipulates the speed switching button, the motor rotational speed switching relay 3 varies the rotational speed of the hood motor 1, in accordance with the contact of the switching terminal T2 with the low-velocity transfer contact L or with the highvelocity transfer contact H, by the selective manipulation of the user through the speed switching button.
Meanwhile, when the temperature in the gas range rises over a certain temperature, the TCO which senses such a temperature rise is switched on. Accordingly, the hood motor 1 is rotatably driven by AC power due to a closed circuit formed by the TCO, even when the switching terminal T1 of the motor driving relay 2 is not switched on to the switching-on contact.
In such a situation, also, the rotational speed of the hood motor 1 is adjusted by the user who manipulates the speed switching button by selectively switching the motor rotational speed switching relay 3.
In the conventional driving controlling apparatus of the hood motor, however, since expensive relays have to be employed to switch on/off the hood motor and to control the rotational speed of the hood motor, the manufacturing cost is considerably higher. Further, as the relays are frequently used, there occurs poor contact of the relays, so that the driving reliability of the circuit is deteriorated.
Accordingly, there is a growing demand for a driving controlling apparatus that can substitute the conventional hood motor driving method employing expensive relays, which is inexpensive, and has higher reliability.